Artificial Blood Vessel Stent

ABSTRACT

The present invention discloses an artificial blood vessel stent, which can minimize the diameter of a stent insertion device because the diameter (profile) thereof is uniform and small over the entire length upon being loaded, and accordingly can be easily placed in a branched portion of a blood vessel using a puncture method. The artificial blood vessel stent comprises: (I) an artificial blood vessel body  1  in which the upper end part is formed with a single cylindrical shape or partially cylindrical shape and the lower end part is divided into two small cylindrical shapes or partially cylindrical shapes having different lengths; (II) a cylindrical first stent member  2  connected to the upper end of the artificial blood vessel body and being expandable; (III) a cylindrical second stent member  3  connected to the shorter side of the lower end part of the artificial blood vessel body and being expandable; and (IV) a cylindrical third stent member  4  inserted into the longer side of the lower end part of the artificial blood vessel body, so that the upper end surface coincides with the lower end surface of the second stent member, and being expandable.

TECHNICAL FIELD

The present invention relates to an artificial blood vessel stent, andmore particularly, to an artificial blood vessel stent which canminimize the diameter of a stent insertion device (hereinafter, ‘cannuladevice’) because the diameter (profile) of the stent is uniform andsmall over the entire length thereof upon being contracted and inserted(loaded) into the insertion device, and accordingly can be easily placedin a branched portion of a blood vessel, such as an artery, using apuncture method.

As an example, aneurysm is characterized by swelling of an artery,similar to the way in which a balloon expands, and is a very seriousdisease since weakened arterial walls may rupture if intravascularpressure increases above a certain level.

BACKGROUND ART

As one method of treating aneurysm, an artificial blood vessel stent hasbeen developed which can solve the problems associated with aneurysmthrough a surgical operation and minimize patient's pains without anoperation when a surgical operation is not applicable to the patient.However, due to the fact that the size of a cannula device used for sucha stent must be expanded to a diameter of more than 6 mm, a cut-downmethod, in which a blood vessel is locally surgically opened followed byinsertion of the stent, has been mainly employed.

Although the said cut-down method is more convenient than full surgicaloperation, it is still inconvenient in that a local operation must beperformed. Furthermore, it is very difficult to insert the stent if theblood vessel is curved or twisted. Thus, the puncture method wasdeveloped and popularized.

The said puncture method is a treatment method in which a fine hole ismade in a blood vessel, particularly, in an artery, without operationlocally opening blood vessel, a stent cannula device then being insertedinto the artery through the hole, and an artificial blood vessel stentthen placed at the lesion region of the artery by means of the stentcannula device inserted into the fine hole.

In order to use the puncture method, the inner diameter of the stentcannula device needs to be lower than, for example, 4 mm, and the outerdiameter thereof needs to be lower than, for example, 4.5 mm.

Moreover, the artificial blood vessel stent has to be contracted to asize smaller than, for example, the inner diameter of the cannula deviceso that it can be inserted into the stent cannula device.

As shown in FIG. 1, however, a conventional artificial blood vesselstent has a monolithic structure in which an inner bare stent isinserted into an artificial blood vessel body and formed integrallytherewith. Thus, the diameter (profile) of the artificial blood vesselstent contracted upon being inserted (loaded) into the stent cannuladevice is more than 4.5 mm.

Due to this, the outer diameter of the stent cannula device used toplace the conventional artificial blood vessel stent as shown in FIG. 1must be larger than 4.95 mm. Thus, it is impossible to place theconventional artificial blood vessel stent in a blood vessel by thepuncture method.

In FIG. 1, illustration of the middle portion of the inner bare stentinserted into the artificial blood vessel body is omitted.

DISCLOSURE OF THE INVENTION

The present invention has been proposed to solve the above problems, andprovides an artificial blood vessel stent which can minimize thediameter of a stent cannula device to less than 4.5 mm because thediameter (profile) of the stent is uniform and small over the entirelength thereof upon separation from an inner bare stent and being loadedinto the cannula device, and accordingly can be placed in blood vesselsusing a puncture method.

Furthermore, the present invention provides an artificial blood vesselstent which is suitable for placement into branch points in bloodvessels, such as arteries, because it has an inverted Y-shapedstructure.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings.

As shown in FIG. 2, an artificial blood vessel stent of the presentinvention comprises:

an artificial blood vessel body 1 which is sufficiently flexible to bebent in any direction and has a structure in which the upper end partthereof is formed with a single cylindrical shape or partiallycylindrical shape and the lower end part thereof is divided into twosmall cylindrical shapes or partially cylindrical shapes havingdifferent lengths, thereby being capable of insertion into a bloodvessel and preventing the intravascular pressure from being applied toweakened walls of the blood vessel;

a cylindrical first stent member 2 that is connected to the upper end ofthe artificial blood vessel body to support the artificial blood vesselbody, and is contractible to a certain size and has a certain degree ofexpandability;

a cylindrical second stent member 3 that is connected to the shorterside of the lower end part of the artificial blood vessel body tosupport the shorter side of the lower end part of the artificial bloodvessel body, and is contractible to a certain size and has a certaindegree of expandability; and

a cylindrical third stent member 4 that is inserted into the longer sideof the lower end part of the artificial blood vessel body so that theupper end surface coincides with the lower end surface of the secondstent member to thus support the longer side of the lower end part ofthe artificial blood vessel body, and is contractible to a certain sizeand has a certain degree of expandability.

Further, a plurality of barbs 5 for fixing the artificial blood vesselstent to a blood vessel are placed at the region connecting theartificial blood vessel body 1 and the first stent member 2.

The barbs are metal wires, whose middle parts are twisted and fixed tothe first stent member 2, and having both opposite end parts thereofprotruded to the outside. They play the role of preventing theartificial blood vessel stent from displacement (migration) due to theforce of blood pressure applied thereto after initial placement of theartificial blood vessel stent.

The first stent member 2, second stent member 3 and third stent member 4may have identical or different structures, and it is preferred thateach of them forms at least one turn so as to have a cylindrical shape.

The artificial blood vessel body 1 is made of a high density fabricwhich is sufficiently flexible to be bent in any direction, and thefirst stent member 2 and the third stent member 4 are made of metal wireor the like being contractible to a predetermined size and having acertain degree of expandability.

As shown in FIG. 1. the artificial blood vessel stent of the presentinvention has a structure in which the lower end of the artificial bloodvessel body 1 is divided into two cylindrical shapes or partiallycylindrical shapes having a different length so that the diameter(profile) becomes uniform over the entire length upon being inserted(loaded) into the stent cannula device. The second stent member 3 isconnected (not inserted) to the shorter side of the lower end part ofthe artificial blood vessel body 1, and the third stent member 4 isinserted into the longer side of the lower end part of the artificialblood vessel body 1 so that the upper end surface coincides with thelower end surface of the second stent member.

Further, the artificial blood vessel stent of the present invention,rather than being formed integrally with the inner bare stent, isseparated therefrom so as to allow the diameter thereof to be reducedupon being inserted (loaded) into the stent cannula device.

Due to this, the artificial blood vessel stent of the present inventionis small and uniform over the entire length, i.e., the diameter thereofis less than 4.0 mm upon being inserted (loaded) into the stent cannuladevice.

As a result, the artificial blood vessel stent can be placed in a bloodvessel using the puncture method since the inner diameter and outerdiameter of the stent cannula device can be minimized.

In particular, in the present invention, the inner diameter of the stentcannula device can become less than 4.0 mm and the outer diameterthereof can become less than 4.5 mm.

As shown in FIGS. 5 and 6, the artificial blood vessel stent of thepresent invention can be inserted and placed into a blood vessel by atypical stent cannula device comprising a cannula device member 10 forreceiving the artificial blood vessel stent, a pusher member 20 forpushing the artificial blood vessel stent out of the cannula devicemember 10 and a catheter 30 having a streamlined tip part 31 formed onthe front end thereof and being placed in the pusher member.

The procedure for placing the artificial blood vessel stent inaccordance with the present invention inside a blood vessel by using thestent cannula device will be described below.

Firstly, as shown in FIG. 5, the artificial blood vessel stent of thepresent invention is contracted and inserted into the front end of thecannulation member 10 of the stent cannula device, and then the frontend of the cannulation member of the stent cannula device is inserted atthe location of a vascular lesion portion of a patient by using a guidemember (not shown) inserted into the catheter 30.

In this state, if the cannulation member 10 is pulled backward with thepusher member 20 fixed, as shown in FIG. 6, the artificial blood vesselstent expands on account of its own elasticity upon being pushed out ofthe cannulation member 10, and is fixedly positioned in the bloodvessel.

FIG. 5 is a cross sectional view of the artificial blood vessel stent ofthe present invention inserted into the cannula device. FIG. 6 is across sectional view of the artificial blood vessel stent of the presentinvention in the process of being pushed out of the cannula device.

A concrete description of how the artificial blood vessel stent of thepresent invention may be used to treat an aneurysm occurring at abranch-portion of a blood vessel will be given below.

As seen from the above, the artificial blood vessel stent of the presentinvention is placed in a blood vessel using the stent cannula device,and then the inner bare stent as shown in FIG. 3 is inserted into theupper end part of the artificial blood vessel stent body 1 placed inadvance in the blood vessel by the same method by using another stentcannula device. Subsequently, the two limb stents as shown in FIG. 4 areinserted into the second stent 3 and third stent 4 of the artificialblood vessel stent placed in advance in the blood vessel by the samemethod by using other stent cannula devices respectively, therebycompleting the treatment of aneurysm of the blood vessel-branchedportion.

FIG. 4 is a front view of a limb stent whose middle part is cut out,wherein illustration of the inner bare stent inserted into the middlepart is omitted.

ADVANTAGEOUS EFFECT

The artificial blood vessel stent of the present invention can minimizethe diameter of a stent cannula device because the diameter of the stentis small and uniform over the entire length thereof upon being separatedfrom an inner bare stent and loaded into the cannula device, andaccordingly is able to be easily placed in a blood vessel using apuncture method.

Moreover, the artificial blood vessel stent of the present invention ismore suitable for placement into a branched portion of a blood vessel,such as an artery, due to the inverted Y-shaped structure thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a conventional artificial blood vessel stent;

FIG. 2 is a front view of an artificial blood vessel stent in accordancewith the present invention;

FIG. 3 is a front view of an inner bare stent which is inserted into atop part of an artificial blood vessel body 1 of the artificial bloodvessel stent of the present invention by another cannular device;

FIG. 4 is a front view of a limb stent that is inserted into a lowerpart of an artificial blood vessel 1 of the artificial blood vesselstent of the present invention by another cannular device;

FIG. 5 is a cross sectional view of the artificial blood vessel stent ofthe present invention inserted into the cannular device; and

FIG. 6 is a cross sectional view showing the artificial blood vesselstent of the present invention in the process of being pushed out of thecannular device.

INDUSTRIAL APPLICABILITY

The artificial blood vessel stent of the present invention is applicableto the treatment of arterial diseases since it can be easily insertedand placed in a branched portion of a blood vessel.

1. An artificial blood vessel stent, comprising: an artificial bloodvessel body 1 which is sufficiently flexible to be bent in any directionand has a structure in which the upper end part thereof is formed with asingle cylindrical shape or partially cylindrical shape and the lowerend part thereof is divided into two small cylindrical shapes orpartially cylindrical shapes having different lengths, thereby beingcapable of insertion into a blood vessel and preventing theintravascular pressure from being applied to weakened walls of the bloodvessel; a cylindrical first stent member 2 that is connected to theupper end of the artificial blood vessel body to support the artificialblood vessel body, and is contractible to a certain size and has acertain degree of expandability; a cylindrical second stent member 3that is connected to the shorter side of the lower end part of theartificial blood vessel body to support the shorter side of the lowerend part of the artificial blood vessel body, and is contractible to acertain size and has a certain degree of expandability; and acylindrical third stent member 4 that is inserted into the longer sideof the lower end part of the artificial blood vessel body so that theupper end surface coincides with the lower end surface of the secondstent member to thus support the longer side of the lower end part ofthe artificial blood vessel body, and is contractible to a certain sizeand has a certain degree of expandability.
 2. The artificial bloodvessel stent of claim 1, wherein a plurality of barbs 5 for fixing theartificial blood vessel stent to a blood vessel are placed at the regionconnecting the artificial blood vessel body 1 and the first stent member2.
 3. The artificial blood vessel stent of claim 1, wherein theartificial blood vessel stent is uniform over the entire length thereof,and has less than 4.0 mm of the diameter upon being inserted (loaded)into the stent cannula device.
 4. The artificial blood vessel stent ofclaim 1, wherein the first stent member 2, second stent member 3, andthird stent member 4 have identical or different structures.
 5. Theartificial blood vessel stent of claim 1, wherein the first stent member2, second stent member 3 and third stent member 4 form at least one turnso as to have a cylindrical or partially-cylindrical shape.
 6. Theartificial blood vessel stent of claim 1, wherein the artificial bloodvessel body 1 is made of a high density fabric.
 7. The artificial bloodvessel stent of claim 1, wherein the first stent member 2, second stentmember 3 and third stent member 4 are made of metal wire.